A recent analysis from the COSMOS randomized controlled trial examined whether a daily multivitamin could influence biological aging in older adults. Researchers evaluated 958 participants (mean age ~70) over a two-year period, comparing a standard multivitamin (Centrum Silver) to a placebo.
Biological aging was assessed using five epigenetic clocks, which estimate aging based on DNA methylation patterns associated with inflammation, organ function, and mortality risk. What they found is quite surprising!
Key Points You Need To Know!
A large randomized controlled trial (COSMOS) found that a daily multivitamin slowed biological aging by ~2.7–5.1 months over 2 years
Benefits were greatest in individuals aging faster at baseline (up to ~18× greater effect)
Three separate studies showed ~2 years of slowed cognitive aging
The likely mechanism involves B vitamins supporting DNA methylation
Multivitamins do not replace diet, exercise, and sleep, but may be useful to fill nutritional gaps
What Is Biological Aging (And Why It Matters)
When most people think about aging, they think in years. But what actually matters is how your body is functioning.
Biological aging reflects changes that occur in the body over time, such as;
Inflammation
Cellular efficiency
Organ function
Researchers measure biological age using epigenetic clocks. These tools analyze chemical markers on DNA to estimate how fast the body is aging at a physiological level.
Some are built using data tied to:
Mortality risk
Disease markers
Organ system decline
When a study shows a change in these measures, it reflects a shift in underlying physiology, not just a change in chronological age (Smith, 2026)
The COSMOS Trial: Daily Multivitamins And Biological Aging
Participants: 958 older adults (~70 years old)
Intervention: Daily multivitamin (Centrum Silver) vs placebo
Duration: 2 years
Outcome: Changes in biological aging using 5 epigenetic clocks
To evaluate multivitamin use and biological aging, data was taken from the COSMOS trial, one of the largest randomized controlled nutrition studies conducted (Li et al, 2026).
Researchers took 958 older adults (average age ~70) and had them take either a daily multivitamin (Centrum Silver) or a placebo for two years.
Instead of just tracking outcomes like weight or blood markers, they measured biological aging using five epigenetic clocks. These clocks estimate how fast the body is aging based on DNA markers tied to inflammation, organ function, and disease risk.
What Were the Results?
After two years, the group taking the daily multivitamin showed slower biological aging on two of the five epigenetic clocks:
PCGrimAge: ~2.7 months slower
PCPhenoAge: ~5.1 months slower
So, over two years, the multivitamin group showed about 2–5 months less biological aging compared to placebo.
What Are Epigenetic Clocks?
PCGrimAge and PCPhenoAge are models that estimate how fast the body is aging based on DNA markers.
PCGrimAge (~2.7 months slower) is built using data linked to mortality risk, including markers associated with inflammation and overall lifespan.
PCPhenoAge (~5.1 months slower) is built around physiological function, using markers tied to things like metabolic health, immune function, and organ performance.
What Does That Actually Mean?
A lower score means those underlying risk processes are progressing more slowly. In practical terms, the multivitamin group showed a small but measurable slowdown in the physiological changes associated with aging.
Who Benefited the Most From Taking Multivitamins?
This is where it gets interesting.
Participants with elevated biological aging at baseline experienced substantially greater benefit, approximately 18 times greater than those aging at a typical rate.
This suggests the effect is not uniform and is likely influenced by baseline nutritional status or physiological strain.
Summary:
Participants who were aging faster at baseline saw up to ~18× greater benefit
Participants who were already aging slower saw less of an effect
The worse your nutritional status or biological aging, the more a multivitamin helps.
Cognitive Improvements Were Consistent Across Multiple Studies
The COSMOS trial also included three separate sub-studies that assessed cognitive outcomes across different populations and methodologies.
COSMOS-Mind
COSMOS-Web
COSMOS-Clinic
Across approximately 5,200 participants, pooled data indicated that multivitamin supplementation slowed cognitive decline to a degree comparable to roughly two years of aging.
Summary:
3 different sub-studies with different populations, methods, and researchers were used
Multivitamin use produced cognitive improvements equivalent to ~2 years of slower brain aging across all studies.
Cocoa extract Showed No Effect
The trial also evaluated cocoa flavanol supplementation. No effect was observed on epigenetic aging, suggesting the multivitamin effect is specific and not attributable to general supplement use.
The trial also evaluated cocoa flavanol supplementation. No effect was observed on epigenetic aging, suggesting the multivitamin effect is specific and not attributable to general supplement use.
Summary:
The trial also tested the effect of cocoa flavanols
Cocoa showed no effect on biological aging
This indicates that the benefit of multivitamins is specific
The Mechanism: Why Do Multivitamins Help Slow Down Biological Aging?
The most plausible mechanism involves B vitamins, particularly:
Folate (B9)
Vitamin B12
Vitamin B6
With aging, B-vitamin status often declines. Estimates suggest that 11–15% of adults over 50 are deficient in vitamin B12 (National Institutes of Health, 2025).
These vitamins help your body maintain the chemical signals that tell your genes how to function. When those signals become less stable with age, often due to lower nutrient levels, cell function declines, and biological aging can accelerate.
Multivitamin supplementation may help maintain these processes by ensuring sufficient availability of key micronutrients.
Summary:
B-Vitamin Complex is believed to play a major role
~11–15% of adults over 50 are deficient in B12
This deficiency can cause cellular function declines as biological aging accelerates
What This Means For You
Here’s the reality: We’ve known this for years:
Nutrient deficiencies impact health
Aging is tied to cellular regulation
Diet quality declines in many populations
What this study shows is that a standard multivitamin can help correct small nutritional gaps and can measurably influence biological aging. Modest reductions can be seen in the aging rate and cognitive decline in older adults.
An interesting finding is that the people who saw the greatest improvements were those aging faster at baseline. While researchers didn’t directly tie the two, it’s reasonable to think they also had lower-quality diets.
In other words, the multivitamins were likely just correcting a deficiency caused by poor diets, showing that micronutrient sufficiency matters.
And this is where people get it wrong.
A multivitamin is:
Not a substitute for whole foods
Not a replacement for training
Not a shortcut
The primary drivers of health and longevity are still:
Resistance training
Energy balance
Sleep
Stress management
However, for individuals with gaps in their nutrition or who want “insurance”, a multivitamin may provide a small but meaningful benefit over time, making it a cost-effective and efficient therapy.
If you’re someone who knows they might have a gap in their nutrition or wants some nutritional insurance, SFS now offers our Complete Multivitamin!
Full-spectrum vitamins and minerals to help fill common nutrition gaps
Prostate-support blend with targeted herbs and key nutrients
Immune system support with antioxidant and micronutrient coverage
B-vitamins + performance enhancers to support energy metabolism and daily output
Check them out as well as our supplements, which we offer to support training, health, and longevity!
FAQ: Multivitamins and Health
1. Do multivitamins actually improve health?
Multivitamins are not a replacement for diet or training, but they can help fill micronutrient gaps. Evidence from large randomized trials suggests they may provide modest benefits in areas like biological aging and cognitive function, particularly in older adults.
2. Can a multivitamin slow aging?
Recent research shows that a daily multivitamin can slightly reduce the rate of biological aging. The effect is modest, but measurable, and appears to reflect the slower progression of physiological processes linked to aging.
3. Who benefits most from taking a multivitamin?
Individuals with gaps in their diet, age-related declines in nutrient absorption, or higher baseline biological aging tend to benefit the most. Those with already optimized nutrition may see smaller effects.
4. Do multivitamins improve brain health?
Data from multiple studies within the same trial found that multivitamin use slowed cognitive decline, with results comparable to delaying brain aging by roughly two years in older adults.
5. Should you take a multivitamin if your diet is already good?
If your diet consistently meets micronutrient needs, the benefit may be minimal. However, multivitamins can still serve as a low-risk way to ensure adequate intake, especially as nutrient absorption declines with age.
References
Mass General Brigham. (2026, March 9). Daily multivitamin intake linked to slower biological aging in older adults. News-Medical. https://www.news-medical.net/news/20260309/Daily-multivitamin-intake-linked-to-slower-biological-aging-in-older-adults.aspx
Li, S., et al. (2026). Effects of daily multivitamin–multimineral and cocoa extract supplementation on epigenetic aging clocks in the COSMOS randomized clinical trial. Nature Medicine. DOI: 10.1038/s41591-026-04239-3. https://www.nature.com/articles/s41591-026-04239-3
National Institutes of Health, Office of Dietary Supplements. (2025, July 2). Vitamin B12: Fact sheet for health professionals [Fact sheet]. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
Smith J. (2026). Daily multivitamin slows signs of biological ageing. Nature, 10.1038/d41586-026-00741-3. Advance online publication. https://doi.org/10.1038/d41586-026-00741-3
